The present invention relates generally to a toner supply device for use in an image forming system, such as a copying machine, a facsimile or a printer. More specifically, the invention relates to a toner supply device for supplying a toner while rotating an exchangeable cylindrical toner cartridge and for breaking local accumulation of the toner in the toner cartridge by rotating the toner cartridge in forward and reverse directions by a predetermined angle during exchange of the cartridge or in a desired situation.
In a typical image forming system, the surface of an electrified photosensitive material drum is electrified, and an image information to be copied is exposed to the surface of the drum to form a latent image. Then, a toner is absorbed into the photosensitive material to form a visible image. This visible image is transferred to the surface of a paper, and the toner is fixed on the surface of the paper by heat and pressure. Then, cleaning and de-electrification are carried out to cause a predetermined image information to be a printed information on the surface of the paper. In a developing process for forming the visible image, the toner, together with a carrier of a magnetic material, is used as a developer.
The carrier serving as a main component included in the developer is used for carrying the toner and producing frictional electrification. Since this carrier is electrified to be used for causing the toner to be absorbed into the photosensitive material drum and the surface of the paper, the carrier does not adhere to the surface of the paper and is not consumed, so that the amount of the carrier does not decrease. On the other hand, although the toner itself is not electrified, the toner is gradually consumed to be decreased when a printed matter is prepared after processes, such as transfer, fixing and cleaning. Therefore, the toner must be supplied as required with the use of the image forming system.
The way for supplying the toner is broadly divided into two methods. One of the methods is a method for providing a cartridge dedicated to the copying machine and for supplying a predetermined amount of toner, which is filled in a container, from a supply port of the cartridge when the residual quantity of the toner in the copying machine is short. According to this method, when the toner is supplied to the cartridge from a container, it is difficult for a usual user to skillfully fill the toner in the small-diameter supply port of the cartridge, if not for experts, so that there is the possibility that the toner spills to dirty user's cloths and/or hands. If the spilled toner is raked up to be put in the cartridge, there is also the possibility that impurities are mixed therein.
The other toner supply method is a method using an exchangeable cartridge. This method is an excellent supply method easy to be used, since the exchangeable cartridge is capable of supplying a toner, which is mixed at the best to cause the image forming system to display the best performance to prepare a copied matter, to the developing part of the image forming system without mixing impurities, and of preventing the user for supplying the toner from spilling the toner or the user's cloths and/or hands from being dirtied.
In order to supply a toner using a conventional toner supply device, an empty cartridge formed so as to have a predetermined shape and standard is detached from a cartridge attaching part of a copying machine, and an exchanged cartridge which has the same shape and standard as those of the empty cartridge and which is filled with a toner, is attached on the cartridge attaching part after being sufficiently shaken. Although there are various shapes and capacities of toner cartridges, there is a cylindrical toner cartridge as one of them. The cylindrical toner cartridge has the merit of being capable of utilizing the inner peripheral wall to efficiently supply a toner to a discharging hole. If the cylindrical cartridge is horizontally arranged, a spiral groove is formed in the inner wall surface of the cylindrical cartridge, or the cylindrical cartridge is rotated about the central axis thereof, so that the toner is guided toward the discharging hole.
However, according to such a conventional toner supply device, there is a problem in that it is difficult to carry out the operation of inserting a toner receiving container of the toner cartridge into a narrow space of an image forming system, such as a copying machine, in a horizontal direction. In particular, there is a problem in that the operation of holding and inserting a very heavy container, which is filled with the toner, by user's fingers is very difficult, although the operation of detaching an empty container, in which a toner is completely consumed, is not so difficult. Therefore, it is important to form a holding part, which can cause the user to surely hold a toner cartridge, on the bottom side of the toner receiving container.
In addition, in a toner cartridge of a type wherein the tip portion of a toner receiving container is formed as a stepped small-diameter cylindrical portion and wherein a toner discharging hole is formed in the periphery of the small-diameter cylindrical portion, the toner discharging hole formed in the periphery is preferably held so as to face upwards. The toner discharging hole is often provided with a shielding cover for shielding the toner discharging hole when the toner cartridge is not attached and for opening the toner discharging hole only when it is required to supply the toner. Even if the shielding cover is provided, the problems in the leakage of the toner and so forth are not serious if the toner discharging hold faces upwards.
In particular, although there is often an opportunity to open the shielding cover during exchange of the toner cartridge, it is important to hold the toner cartridge while turning the toner cartridge upwards until it is required to actually supply the toner to a developing device. However, during exchange of the toner cartridge, there is a problem in that the direction of the toner discharging hole provided in the tip side can not be confirmed from the bottom side. Therefore, it is requested that the direction of the toner discharging hold provided in the tip cylindrical portion of toner cartridge, which begins to be inserted inside of a body, such as a copying machine, can be confirmed from the bottom side.